Recirculation underjet coking retort oven



May 7, 1968: J. VAN ACKEREN RECIRCULATION UNDERJET COKING RETORT OVEN 5 Sheets-Sheet 1 Filed Jan. 9, 1963 N N11: h. N: \u a \N NN Juli May 7, 1968 J. VAN ACKEREN RECIRCULATION UNDERJET COKING RETORT OVEN 5 Sheets-Sheet Filed Jan.

INVENTOR. Jam-p VAN HCKEREM SECTION SECTION RECfRCULATION UNDERJET COKING RETORT OVEN 5 Sheets-Sheet Filed Jan.

. a va d 2 a K wk 5 m A May 7, 1968 J. VAN ACKEREN RECIRCULATION UNDERJET COKING RETORT OVEN 5 Sheets-Sheet 5 Filed Jan. 9. 1963 INVENTOR. Jase/ w VAN Ac/rERE/V nrronwzv United States Patent 3,382,156 RECIRCULATHON UNDERJET QOKING RETGRT OVEN Joseph Van Acl-reren, Pittsburgh, Pa, assignor to Koppers Company, Inc, a corporation of Delaware Filed .lan. 9, 1963, Ser. No. 250,337 1 Claim. (Cl. 262-141) ABSTRACT 0F THE DESCLOSURE A high chambered regenerative coke oven with low and high level burners supplied by split-flow nozzles.

This invention relates to improvements in the construction and general operation of underjet waste gas recirculating-type regenerative horizontal coking retort ovens having coking chambers of substantial increase in height over the height of conventional coking chambers and employing both a low burner and a high burner in each flame flue. More particularly, this invention is directed to the structural arrangement of the underjet regulating assemblies and fuel gas risers whereby a minimum number of these regulating assemblies with attendant facility for separate external control of fuel gas flow to the high and low gas burners in each flue may be provided.

The conventional coke oven battery contains coking chambers each of which is about forty feet long, about eighteen inches wide and about thirteen feet high. When charged, each coking chamber contains about eighteen tons of coal. The primary objective of the constructors of coke oven structures has for some time been to substantially increase the production capacity of by-product coke ovens to reduce the unit production cost of coke to maintain for this material its competitive position in the metallurgical industries.

A number of arrangements and proposals have been ofiered in this regard, however, no one of these attempts has met with any great degree of success, because the problem is not simply one soluble by building higher or wider coke ovens into which larger quantities of coal can be charged but, rather, one soluble only by insuring that whatever coal is charged into these larger coking chambers will be converted to coke of uniform quality having the structure and composition required for use in the metallurgicalindustries. In order to produce coke of this quality it is important that strict uniformity be maintained in the distribution of heat to the coal in the coking chamber during the coking process. True, this has been the same problem that has faced the art for many years in the construction of coke ovens of conventional capacity and after much study and design this problem of uniform heating was eventually solved for the case of coke ovens of conventional capacity. However, this know-how may be directly applied only in the design and operation of those ovens in which the aforementioned conventional height of about thirteen feet or less is maintained.

Investigations have shown that changing the width of the coking chamber has essentially no effect on coke production. It is clearly acknowledged that increasing the width of the coking chamber will not increase the output of coke per unit of time and, if the coking chamber is narrowed, less coke tonnage can be pushed for the same pushing cost as is now expanded with standard 18" oven chambers. The only solution is to design coking chambers so that greater coke tonnage can be pushed than is now pushed from standard coking chambers but with little or no increase in pushing expense. It appears therefore that the only approach to the more economical production of metallurgical coke lies in increasing the Patented May 7, 1968 ice capacity of the coking chambers by increasing the height and length thereof.

With the acceptance of this fact, it becomes manifest that an entirely new empirical approach must be developed to insure the uniform distribution of heat to the coals in these higher-than-conventional coking chambers, particularly, in those instances in which the height of the coking chamber has been increased by as much as fifty percent.

The construction and modes of operation proposed for coking chambers of such increased height to date have been unable to provide this requisite uniformity of heat distribution, which is essential not only to the production of coke suitable for metallurgical applications, but also to the successful distillation of such by-products of coke-making as benzol and toluol, which in addition to other by-product chemicals are peculiarly subject to destruction during this process. Further, once the operator is given a pushing schedule to meet, unless he can count on uniform heat distribution to the coal in the coking chamber at predictable rates, then the quality of the prodnot leaving the coking chambers according to the selected pushing schedule will not be controllable and the operator cannot consistently produce an optimum grade of coke.

It has logically been concluded by many skilled in the art that to uniformly heat walls of increased height sole reliance cannot be placed upon combustion from burners near the base of the flame flues. Supplementary heat must also be supplied at a higher level and, for this reason, high burners in addition to the conventional low burners have been employed.

With the use of high burners to extend the heat of combustion to the upper regions of these taller flues, two problems have arisen. First, clogging of the fuel gas riser passages leading to the high burners and second, the increased initial and maintenance costs of providing double the number of underjet gas regulating assemblies to accommodate the added number of high gas burners. Clogging of the high burner riser passages occurs primarily in the region between the base of the flue and the high burner ports or nozzles. This clogging is caused by the deposition in the riser passages of carbon formed during the thermal decomposition of the rich fuel gas conducted therethrough to the high burners.

It is thus the object of this invention to provide unique construction whereby the number of gas regulating assemblies is substantially not increased over the number of regulating gas nozzle assemblies normally employed in a conventional type battery in spite of the addition of another gas port within each flue and to provide an arrangement of high burner risers and ports whereby waste gas recirculation therethrough to decarbonize the rich fuel gas supply risers is retained while increasing the exposure of flame-flue liner walls to uniform heating and facilitating the disposition of the requisite plurality of ports in each flame-flue.

In brief, therefore, to enable the construction of high capacity by-product coke ovens having coking chambers of a height exceeding that of conventional coking chambers by approximately fifty percent to produce coke for metallurgical uses, this invention consists of splitting the gas flow from each regulating gas nozzle assembly either to service a pair of high level burners or to service a pair of low level burners whereby both a high level burner and a low level burner may be employed in each flue using the same number of regulating gas nozzle assemblies as have been previously required for supplying fuel gas to a single burner in each flue of a conventional battery.

In the accompanying drawings forming part of this specification, there are shown for purposes of illustration underjet batteries of the Koppers-Becker design (crossover flue interconnected combustion flue heating system) embodying this invention. Although this invention is preferably employed in combination with waste gas recirculation construction, it isnot limited in its application to this specific type of oven, but is broadly applicable to underjet-fired batteries.

FIG. 1 is a diagrammatic vertical section taken along line I-I of FIG. 2 transversely of an underjet coke oven battery employing rich fuel gas feed both to the high burners and to the low burners with the splitting of the gas flow from each regulating assembly to a pair of risers occurring at about the elevaion of the sole flues;

FIG. 2 is a diagrammatic partial vertical section longitudinally of the underjet battery illustrated in FIG. 1 with the left half thereof taken along line A-A of FIG. 1 and with the right half thereof taken along line B-B of FIG. 1;

FIG. 3 is an enlarged sectional view showing the arrangement in expanded position of the regulating gas nozzle assemblies and risers in the region of the sole flues where the gas flow splits and passes into a pair of risers above the regulator assembly;

FIG. 4 is a partial vertical section longitudinally of an underjct battery employing a second embodiment of the invention wherein the gas fiow from each gas regulating assembly is split and passes to two flues via a pair of risers with the splitting of the gas flow occurring in the corbel area;

FIG. 5 is a partial vertical section transversely of the same battery taken on line V-V of FIG. 4 and showing in greater detail the orientation of the risers to the burners, particularly of the high burner risers which pass upward through the bottle brick of the tie walls within the heating wall;

FIG. 6 is an enlarged detail partially in section of the novel two-holed nozzle with its positioning means;

FIG. 7 is a view of the underside of the nozzle shown in FIG. 6;

FIG. 8 is a detail in section of the receptacle for housing the nozzle shown in FIG. 6 and FIG. 9 is a view taken on line IX-IX of FIG. 8.

Throughout the specification the terms conduits, risers and pasageways will be used interchangeably to designate means for conveying gases to and from the high and low level burners in the respective fiues.

The coke oven battery 10 illustrated in the accompanying drawings (FIGS. 1 and 2) comprises in general a plurality of coking chambers 11 and heating walls 12 that are disposed in alternation progressing in the lengthwise direction along battery 10. Heating walls 12 are made up of a series of vertical flame-fines 13, which are individualized heating chambers, disposed in side-by-side relationship extending crosswise of battery 10. These vertical flame-fiues 13 are arranged in groups in order to provide collective fiow of the several flame-fiues 13 in each group to a common crossover duct 14, whereby the combustion products of each flue flow upward, along common horizontal bus flue 16 for each such group of flues, through duct 14 over the top of coking chamber 11 and down into the corresponding group of flame-Hues 13 on the other side of the intermediate coking chamber 11. Thus, each crossover duct 14 can be considered as connecting two flow groups" of flame-flues 13, one of each such pair of connected flow groups receiving for a period the waste combustion gases from the burning operation being conducted in the other group of the pair. At the end of this period the system is reversed and thereby the relative functions of these flow groups cyclically alternate.

Below the coking chambers 11 in the lower story of the oven are arranged a series of cross-regenerators 17 extending in a direction parallel to the series of vertical flame-fines 13 in each heating wall 12 and communicating directly therewith. This communication between flameflues 13 and cross-regenerators 17 is achieved through regenerator port and duct assemblies 18.

Although, as is typical for by-product coke ovens, the battery may be heated by the use of regeneratively preheated lean fuel gas, the illustration of this invention is primarily concerned with the operation during which heating flues 13 are underfired with unpreheated rich fuel gas, such as coke oven as. During such operation, all of the cross-regenerators 17 are employed to preheat combustion air to be delivered to flame-ilues 13 through the port and duct assemblies 18. In those instances in which it is desired to underfire with lean gas supplementing the lean gas from the regenerators with an enriching mixture delivered through the distribution system described herein for rich gas underfiring, this invention is equally applicable.

The rcgenerators 17 contain checker-brick and are divided, in the manner well-known in the art, into two sets which operate in alternation, one set receiving the hot combustion products leaving the off set of flame-Flues 13 thereby to impart heat to the checker-brick therein and the other set simultaneously imparting the heat previously stored in checker-brick to the air passing therethrough during its passage to flame-fines 13. The air so heated reaches a temperature of at last 2000 F.

When battery 10 is underfired with rich fuel gas, which gas has higher calorific value and therefore needs no preheating for eflecting coking temperatures quickly and reliably in the flame-fines 13, this rich gas is delivered to high burners 21 and low burners 22 (one of each in each flame-flue 13) through a series of separate conduits or risers 23, 24 and 26, 27 respectively.

Instead of being arranged in the conventional manner wherein each of risers 23, 24, 26 and 27 would extend down through the brickwork of regenerator pillars 28 to communicate individually with separate regulating gas nozzle assemblies, the arrangement shown in FIGS 1, 2 and 3 requires a greatly reduced number of regulating gas nozzle assemblies employing substantially as many regulating gas nozzle assemblies as would previously have been used in a conventional underjet-type battery having but a single burner in each flame-flue 13.

As shown in FIGS. 1 and 3, high burner risers 23 and 24 serving adjacent flame-fines 13 approach each other in the vicinity of the sole flues 29 and converge in a common juncture at zone 31 which is in line with and in communication with high burner regulating gas nozzle assembly 32. In this fashion the upwardly-directed gas flow input from each regulating gas nozzle assembly 32 is split so that about one half of the total flow passes upward through high burner riser 23 and the balance passes upward through high burner riser 24. To more effectively promote entry of the fuel gas into risers 23 and 24 and to insure the requisite degree of aspiration of waste gas for recirculation thereof, the two-holed nozzle 30 to be described in greater detail below is employed. Because of the slight difference in static pressure in those adjoining fiues with which risers 23 and 24 communicate compensatory balancing of the fuel gas feed to risers 23 and 24 is provided by the use of restrictors 33 and 34 positioned in risers 23 and 24 respectively.

Similarly, the low burner risers 26 and 27 approach each other and converge in a common juncture at zone 36 in the region of the sole flues 29. Zone 36 is in alignment with and receives the fluid delivery from low burner regulating gas nozzle assembly 37. As described herein above in connection with high burner risers 23 and 24, the total fluid input from nozzle assembly 37 is split in passing through the two-holed nozzle 30 with about one half of this gas flow being taken by low burner riser 26 and the balance being taken by low burner riser 27. Restrictors 38 and 39 are provided to compensate for any slight difference in static pressure in those adjoining flues serviced by risers 26, 27. As is evident from FIG. 1 in the arrangement illustrated any given series of risers 23, 24,

26, 27 will contribute fuel gas flow to three separate flues 13 consecutively arranged.

As shown best in FIG. 3, zones 31 and 36 are at opposite ends of a common plenum chamber 41, which serves as the distributing channel for the waste gas recirculated from the ofl? flues 13 to the on flues 13 via off risers, 23, 24, 26, 27; the counterpart plenum chamber 41, and waste gas recirculating duct 42 disposed in concrete pad 43.

To afford greater external control over the fuel gas feed to the high and low burners separate rich fuel gas mains 44, 46 are employed with gas main 44 being connected to all high burner headers 47 and with gas main 46 being connected to all low burner headers 8. Thus, during underfiring of underjet battery with rich fuel gas, this fuel gas fed from the gas mains 44, 46 which extend along opposite sides of battery 10, passes to each header 47 and 48 respectively which is in communication therewith through those of the reversing valves 49 which have been moved to open position to place the fuel gas supply in registry with the on heating walls 12.

Each header 47 communicates with a series of regulating gas nozzle assemblies 32 arranged therealong transverse of battery 10 and each header 48 likewise communicates with a series of regulating gas nozzle assemblies 37 whereby the fuel gas for the high burners passes through nozzle assemblies 32, splits in zone 31 and passes upwardly through high burner risers 23 and 24 to a pair of adjoining flues 13. Simultaneously fuel gas leaving nozzle assemblies 37 splits in zone 36 and passes upwardly through low burner risers 26 and 27 to contribute to the fuel demands of a pair of adjoining lines 13.

As each pair of high 'burner risers 23, 24 extend upwardly each high burner riser twists so that at some point below the level of the floor of the heating walls 12 the pair of high burner risers 23, 24 is re-oriented at 90 to their relative positions in pillar wall 28. It this reoriented position each pair of high burner risers 23, 24 is arranged conveniently for location in the bottle brick of tie walls 53 with each riser venting into a different flue 13 as shown.

Requisite heated combustion air is received by the on flame flues from the appropriate regenerators 17 through port and duct assemblies 18 and the fuel gas delivered in the lower region of each on flue 13 is burned with part of the combustion air so supplied and the fuel gas delivered to the upper region of each on line 13 is burned with the remainder of the combustion air so supplied.

The quantities of fuel gas passing through the high level burners 21 and the low level burners 22 can 'be separately controlled externally of battery 10 by maintaining different pressures in the gas mains 44, 46 and by setting valves 51, which are located between reversing valves 49 and fuel mains 44, 46, as desired. In this manner a more uniform temperature gradient may be provided over the vertical extent of the liner walls 52 of on flues 13 to produce more uniform heating of the higher-than-conventional coking chambers 11.

In the off fines 13 wherein downwardly-directed combustion gases are received from the on flues 13 via crossover ducts 14 and horizontal bus flues 16, most of these gases pass downward to the appropriate regenerator 17 (waste heat) via the connecting port and duct as semblies 18.

However, part of the volume of waste gas in the off flues 13 is sucked down through idle high burner risers 23, 24 and idle low burner risers 26, 27 to the plenum chambers 41 communicating therewith and is drawn through the waste gas recirculating ducts 42 to the counterpart plenum chambers 41 disposed below the adjacent on heating walls 12. The volume of waste gases so removed from the off flues 13 is then aspirated into the risers 23, 24, 26 and 27 in the manner well known in the art by the action of the rich fuel gas ejected from the twoholed nozzles 30 in nozzle assemblies 32 and 37 and directed into the aforementioned risers. In this fashion the rich gas feed is sufliciently diluted so that cracking of the rich gas with subsequent car-bon deposition is obviated.

The provision of special two-holed refractory nozzle plug 30 to insure the introduction of the split streams of fuel gas feed into each corresponding pair of risers introduces the additional complication of insuring the proper orientation of holes 54, with respect to the risers. As shown in FIGS. 3 and 6-9 the nozzle unit 56 is located as in FIG. 3 after being inserted up through nozzle tube 57 from below. Thread segments 58, 58 and shoulder 59 are proportioned to permit passage of these portions into receptacle 60 but not through the top 61 thereof. Matching inclined portions 62, 62 to receive thread segments 58, 58 protrude inwardly from the wall surface of receptacle 60. Upon counterclockwise rotation of nozzle unit 56, thread segments 58, 58 engage inclined portions 62, 62 and advance nozzle unit 56 into receptacle 60. When the nozzle unit 56 has been rotated through the angle 0 (FIG. 7), stops 63, 63 abut the ends 64, 64 of the inclined portions 62, 62, gasket 65 is compressed between shoulder 59 and the top 61 and holes 54 and 55 are properly oriented such that when battery 10 is in the heated condition (FIG. 3), the longitudinal axis of holes 54, 55 are aligned with the longitudinal axes of the appropriate pair of risers.

In battery illustrated in part in FIGS. 4 and 5, instead of having the split in fiow of the rich gas feed occur in the vicinity of sole fines 71, gas feed riser ducts 72 leading to high burner risers 74, 76 and gas feed riser ducts 73 leading to low burner risers 77, 78 respectively extend upwardly through the regenerator walls 79 into the corbel area of the regenerator construction before the split in flow is effected. However, as is shown in FIG. 5 the same general pattern of fuel service as is illustrated in FIGS. 1, 2 and 3 for the fiues 13 is retained in that each single riser duct 72 services the high burners 81 of two adjoining fines and each single riser duct 73, likewise, services the low burners 82 of two adjoining lines.

The disposition of the high b-urner risers 74, 76 relative to each other in the bottle brick of tie walls 83 (as in the case of high burner risers 23, 24 in tie walls 53) is considered particularly advantageous. In this arrangement the split of fuel feed from riser 72 to high burner risers 74, 76 is accomplished substantially at right angles to the split of fuel feed from risers 73 to low burner risers 77 and 78.

This arrangement of high burner risers in the bottle brick as shown in both batteries 10 and 70 enables considerable easing of the crowded conditions in flame flues 84 particularly with respect to the arrangement at the base thereof where in addition to providing room for low burner 82 space must also be allotted to accommodate the air ports 86. In addition, with this arrangement much more of the area of the heating wall surfaces of flame flues 84 receive equal exposure to the flame with the result that more uniform heating of liner walls 87 is secured. Because the bottle brick of which tie walls 83 are composed are about 6 to 7 inches thick, the bottle brick by their very massiveness provide for a reduction in the occurrence of cracking of the rich fuel gases as they pass through risers 74, 76 to high burners 81.

The operation of battery 70 is similar to that described for underjet battery 10. Thus, during underfiring of underjet battery 70 with fuel gas, the fuel gas fed from the gas mains (not shown), which extend along opposite sides of battery 70, passes to each header 88 (for high burners) and each header 89 (for low burners) in communication therewith through appropriate reversing valves (not shown).

Each header 88 extends transversely of battery 70 and communicates with a series of regulating gas nozzle assemblies 91. Each header 89 likewise extends transversely of battery 70 and communicates with a similar series of regulating gas nozzle assemblies 92. Fuel gas feed for the high burners 81 passes through nozzle assemblies 91, is ejected into and passes upwardly through the gas feed riser ducts 72, aspirating and mixing with recirculated waste gas and splits in the corbel region above regenerator pillar walls 79 after which the fuel gas passes through high burner risers 74, 76 to service the high burners 81 in a pair of adjoining fiues 84.

Simultaneously, fuel gas feed leaving nozzle assemblies 92 is ejected into and passes upwardly through riser ducts 73, aspirating and mixing with recirculated waste gas and splits in the corbel region above regenerator pillar walls 79 after which the split feeds of fuel gas pass through low burner risers 77, 78 to service low burners 82 in a pair of adjoining flues 84.

The heated combustion air required to burn the fuel gas so delivered to the flame flues 84 passes from the appropriate regenerators 93 to the on lines 84 through port and duct assemblies 94. Part of the combustion air so supplied reacts in the lower region of each on fine 84 with the fuel gas delivered to this region by low burners 82. The balance of the combustion air is carried up the flue 84 and supports the combustion in the upper region of the flue 84 of the fuel gas entering the on flue 84 from high burners 81.

The quantities of rich fuel gas passing to the high level burners 81 and the low level burners 82 can be separately controlled from the basement area externally of battery 70 in the manner described in connection with the first embodiment to enable the more uniform distribution of heat from top to bottom of the liner walls 87.

In the off flues 84 wherein downwardly-directed combustion gases are received from the on fines 84 via crossover ducts 96 and horizontal bus flues 9'7, most of these gases pass downward to the appropriate regenerators 93 (waste heat) via the connecting port and duct assemblies 94.

Part of the volume of waste gas received in the off flues 84 is, however, sucked down through the idle high burner risers 74, 76 and idle low burner risers 77, 78 thence downwardly through riser ducts 72, 73 respectively to the waste gas recirculating ducts 98 to be aspirated into the rich gas distribution system servicing the on fiues 84 in the manner well known in the art. It may be seen, therefore, that with the arrangement of the high burner risers 74, 76 disclosed not only is the rich fuel gas feed passed upwardly through the bottle brick tie walls 83 but, in the fashion described, waste gas is drawn down through the high burner risers 74, 76 through the bottle brick of these tie walls 83 for recirculation thereof.

Restrictors 99, 101 and 102, 103 are employed in risers 74, 76, 77 and 78 respectively to offset slight differences in pressure in the adjoining fiues 84 supplied with fuel gas from a common riser in the fashion described in connection with the embodiment illustrated in FIGS. 1, 2 and 3.

Thus, with the novel arrangements of regulating gas nozzle assemblies and burner risers disclosed herein, economies can be effected in the number of nozzle assemblies required to service a larger number of burners, regulation and control of the fuel-gas feed to the high and to the low burners can be effected externally of the battery and the crowded conditions which would normally occur within the individual flame flues as the result of introducing both a high and a low burner to each flue are greatly ameliorated.

Various modifications are contemplated and may obviously be resorted to by those skilled in the art without departing from the spirit and scope of the invention, as hereinafter defined by the appended claim, as only preferred combinations of elements have been disclosed.

What is claimed is:

1. A high. chambered regenerative coke oven comprisan elongated coking chamber having a first elongated heating chamber on one side thereof and a second elongated heating chamber on the opposite side thereof,

said heating chambers each including a plurality of spaced vertical heating walls forming separate flues in side by side relation,

crossover ducts extending over said coking chamber and connecting groups of ilues in said first heating chamber with groups of flues in said second heating chamber so that the gaseous products of combustion from one heating chamber are conveyed through said crossover ducts into the other heating chamber,

each of said flues having a high level burner and a low level burner,

pairs of elongated regenerators arranged below and parallel to said heating chambers,

duct means connecting a pair of regenerators with each of said heating chambers for conveying combustion air upwardly from said regenerators to said flues and for conveying waste gas downwardly from said lines into said regenerators,

elongated horizontal sole flues positioned below said regenerators,

other duct means connecting said regenerators to said sole flues for conveying combustion air to said regenerators and for conveying waste gas from said regenerators,

a source of fuel gas,

a first horizontal header connected to said source of fuel gas and extending parallel to said first heating chamber below said horizontal sole fiues,

a second horizontal header connected to said source of fuel gas and extending parallel to said first header below said horizontal sole flues,

a first low level burner vertical riser passageway opening into a low level burner in one of said flues in said first heating chamber and extending downwardly to an elevation adjacent said sole fiues,

a second low level burner vertical riser passageway opening into a low level burner in a flue adjacent to said last named flue in said first heating chamber and extending downwardly to an elevation adjacent said sole fiues,

said first low level burner vertical riser passageway and said second low level burner vertical riser passageway converging toward each other adjacent said sole flues and terminating in a common juncture,

a first vertical conduit connected at one end to said first horizontal header and at the other end to said juncture of said first low level burner vertical riser passageway and said second low level burner vertical riser passageway so that a pair of low level burners are supplied with fuel gas from said header through a single vertical conduit,

a first gas nozzle having a pair of diverging passageways positioned in said first vertical conduit adjacent said juncture of said first and second low level burner vertical riser passageways, said first gas nozzle arranged to split the flow of fuel gas from said first horizontal header into two substantially equal streams and direct said streams into said respective vertical riser passageways so that a single gas nozzle controls the flow of fuel gas to a pair of low level burners,

means to orient said first gas nozzle to align said diverging passageways with said respective low level burner vertical riser passageways,

a first high level burner vertical riser passageway opening into a high level burner in one of said lines in said first heating chamber and extending downwardly to an elevation adjacent said sole flucs,

a second high level burner vertical riser passageway opening into a high level burner in a flue adjacent to said last named flue in said first heating chamber and extending downwardly to an elevation adjacent said sole flues,

said first high level burner vertical riser passageway and said second high level burner vertical riser passageway converging toward each other adjacent said sole Said nozzles having a body portion with a pair of fines and terminating in a common juncture, vertically diverging passageways therein, outwardly a second vertical conduit connected at one end to said extending inclined portions and vertical abutment second horizontal header and at the other end to said means, and

juncture of said first high level burner vertical riser 5 said nozzle shoulder portions positioned on said conpassageway and said second high level burner riser duit support means shoulder portions with said nozzle passageway so that a pair of high level burners are body portion vertical abutment means abutting said supplied with fuel gas from said second header conduit support means vertical abutment means to through a single vertical conduit, thereby orient said pair of vertically diverging pasa second gas nozzle having a pair of diverging passage- 10 sageways in substantial alignment with said respecways positioned in said second vertical conduit adfi Vertical riser p y jacent said juncture of said first and second high level burner vertical riser passageways, said second gas References Cited nozzle arranged to split the flow of fuel gas from said UN STATES PATENTS second horizontal header into two substantially equal 15 streams and direct said streams into said respective 1 g fi vertical riser passageways so that a single gas nozzle 2224920 12/1940 Otto 2O2 141 c ntrols the flow of fuel gas to a pair of high level 476112 5/1949 Rueck'e'l 202 142 burners, means to orient said second gas nozzle to align said 20 gig 33 222; 22222; %g%:ig

diverging passageways with said respective high level 3192127 6/1965 Van g g' g g "'i 51 X burner vertical rrser passageways, 3192129 6/1965 Becker .202 143 said vertical conduits include support and orienting mans for Sald gas 022165, JOSEPH SCOVRONEK, Primary Examiner.

said support means including inwardly extending inclined shoulder portions and vertical abutment MORRIS WOLK: Examme means, 

